Preheat oven to 350 degrees. Slice off 3/4-inch from the pointy end of the garlic to expose a bit of each clove. Place garlic heads in center of a square of aluminum foil, cut side up. Sprinkle on a few drops of water, drizzle on the olive oil, and sprinkle on the salt and pepper. Pull corners of foil up to enclose and fold over to seal. Place package in oven and roast 50 to 60 minutes, until garlic cloves are soft and golden brown. Remove from oven and allow to cool. Squeeze out garlic pulp by squeezing head in half over a bowl. Spread on bread, use as base for dip or dressing.